Insulator



FIG. 1 is environmental perspective view showing a top and a side of an electrical insulator according to the design, the post, clamps and wire being shown in phantom and forming no part of the design;

FIG. 2 is a perspective view showing a top and the other side of an electrical insulator according to the design;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is an end elevation view thereof;

FIG. 6 is an opposite end elevation view thereof;

FIG. 7 is a side elevation view thereof; and,

FIG. 8 is an opposite side elevation view thereof. 

I claim the ornamental design for an insulator, as shown and described. 